The invention relates to an apparatus for analyzing a golf swing or other biomechanical movement used repetitively in sports activity or simulated sports environmental activity setting or to assess medical and biomechanical functions of the human body, specifically to such an apparatus employing dual force plates.
Elements and characteristics of an individual's performance during a physical, biomechanical or other sports activity, such as swinging a golf club or tennis racquet, kicking a soccer ball or football, can be analyzed to improve and optimize performance and develop better technique. This requires computerized input and analysis, since the activity during the relevant action is quick, and multiple elements are occurring nearly simultaneously, often beyond the conscious knowledge of the player involved. When all of the data is collected and analyzed, it needs to be conveyed back to the golfer or other player in an immediate and easily comprehensible way so that difficulties can be noted and corrected with repetition of the activity and comparative re-analysis.
Sports action analysis devices, often golf swing devices with other adaptations possible, have been available for decades. In their simplest computerized form, the devices include a foot plate or plates and sensors to analyze weight shift. These have evolved in complexity as computers have evolved, and current devices outstrip their predecessors in ability to analyze the components of a golf swing or other repetitive sports move, although an optimum device has yet to be developed.
Kretsinger (U.S. Pat. No. 3,169,022) patented a simple device in 1965 that contains two completely independent foot plates and a row of indicator lamps in front of each that light up to show which foot bears most of the weight; the light pattern freezes at the time of ball strike. No memory of the swing is available, and swing to swing comparison is not possible.
Other later devices, such as those seen in work by Bregman (U.S. Pat. No. 5,118,112), Heisler (US Pat. No. 5,150,902), Cromarty (U.S. Pat. No. 5,419,562), and Nesbit (U.S. Pat. No. 6,402,635), feature small, independent footplates that have to be separable and able to be angled in relation to each other to accommodate the golfer's most comfortable stance. Such plates can determine the proportion of total weight on each, but cannot provide data on center of gravity because the computer does not know the position of one in relation to the other. The foot pads can also potentially slip apart during use.
Several of the devices, notably those of Heisler and Cromarty and another by Cecchin (U.S. Pat. No. 6,039,658), include two foot plates that measure total weight on each foot, but are unable to differentiate weights from different portions of the foot, such as the heel and toes or the inside versus the outside of the foot. Data from these devices is often in the form of two continuous, intertwining graphs, one from each foot's weight during the weight shifting of a swing, sometimes shown along with a video image of the golfer.
Detailed interpretation of these lines and correction of the swing often requires the assistance of a skilled third party.
Advances in the art produced devices that could differentially measure the forces of the toe and heel portions of the foot. Bregman asserts this, but does not specifically teach how this information is collected. Nesbit and Mooney (U.S. Pat. No. 7,946,928) have cantilevered devices to measure heel and toe weights, but in each case the foot pads, like Bregman's, are separate and movable, so the center of gravity cannot be measured.
Key components of a golf swing have been chosen in the past as the focus of the devices. There has been some disagreement about which features are the most key. Bregman's and Cecchin's devices collect data from three non-identical points in the swing. Cecchin requires the activation of a timer at pre-swing, apparently by a third party, which takes measurements then and at two other timed points, which are presumed to be maximum backswing and follow-through. This raises the possibility that these measurements may be slightly off of the maximums that should be measured if the swing does not progress at the presumed speed. Mooney's device concentrates on six featured areas of the swing, from addressing the ball through follow-through. It compares the player's golf swing to previously-loaded typical and probable sequences and times of occurrence of feature events in golf swings. It determines the timing of the selected feature events of the player's swing by assigning probabilities of finding feature events at different time periods of the swing by comparison to when these events occur in the sample information. This also raises the possibility that the actual times when the feature events occur in the player's swing may not be exactly when predicted and measured by the pre-set timing parameters of the device.
Measuring parameters from the entire swing, not at pre-selected and possibly not entirely accurate moments, would be optimal to give the player data from the true key points and the fullest amount of possible feedback so that he could work on smoothly correcting his deficiencies throughout his sports action and chart his overall improvement.
In addition, a common disadvantage of the previous devices has been that they have been non-portable and connected to computers via bulky cables.
None has been capable of being taken outside for simulation in the yard or at an actual driving range or golf course.
From the foregoing, it is apparent that improvements are needed to produce such a more complete and versatile sports action device.